Children have their breakfast at the "Vina de Tijuana AC" migrant shelter in Tijuana, Mexico, Saturday, April 28, 2018. As the migrants prepare to walk to the "Casa del Tunel" to get legal advice from U.S. immigration lawyers, they are telling Central Americans in a caravan of asylum-seekers they may... (AP Photo/Hans-Maximo Musielik)Children have their breakfast at the "Vina de Tijuana AC" migrant shelter in Tijuana, Mexico, Saturday, April 28, 2018. As the migrants prepare to walk to the "Casa del Tunel" to get legal advice from... (AP Photo/Hans-Maximo Musielik)

(Newser)
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Hundreds of Central American migrants arrived at the US border Sunday for a rally, to be followed by a planned mass attempt to apply for asylum, in a direct challenge to the Trump administration. The migrants, many traveling with children, left a downtown Tijuana shelter where they had been staying. Police with flashing lights escorted the buses to a cross-border rally at a Pacific Ocean beach, with supporters gathering on both sides of security fencing. President Trump and members of his Cabinet have been tracking the caravan of migrants, calling it a threat to the US since it started March 25 in the Mexican city of Tapachula, near the Guatemala border. Attorney General Jeff Sessions called the caravan "a deliberate attempt to undermine our laws and overwhelm our system," pledging to send more immigration judges to the border to resolve cases if needed.

Trump administration officials have railed against what they call "catch-and-release" policies that allow people requesting asylum to be released from custody into the US while their claims make their way through the courts in a process that can last a year, per the AP. The arrival at San Diego's San Ysidro border crossing, the nation's busiest, marked the end of a monthlong journey by foot, freight train, and bus for the migrants, many of whom said they feared for their safety in their homes. Travelers faced an uncertain future as they prepared to turn themselves in and face asylum. US immigration lawyers conducted free legal workshops for the group, warning them they face possible separation from their children and detention for many months.